[1] Univ British Columbia Okanagan, Sch Nursing, Fac Hlth & Social Dev, Kelowna, BC V1V 1V7, Canada
[2] Univ British Columbia, Dept Pediat, BC Injury Res & Prevent Unit, Vancouver, BC, Canada
[3] Univ British Columbia, Sch Populat & Publ Hlth, BC Childrens Hosp Res Inst, Vancouver, BC, Canada
[4] Univ British Columbia, BC Injury Res & Prevent Unit, Vancouver, BC, Canada